


The Public Restroom Incident

by rehliamonster



Category: Undertale (Video Game)
Genre: Clothing Kink, Don't get caught kink, F/M, Gross, Guilt, Guilty fap, Masturbation, Praise Kink, Public Masturbation, Sans get a reign on your dick, Sans is a gremlin, Shame, Smut, because Reader doesn't know what he's doing to her top, dubcon, indecent use of bikini tops, quiet kink, the party incident
Language: English
Status: Completed
Published: 2018-12-10
Updated: 2018-12-10
Packaged: 2019-09-15 21:40:00
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,111
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16941228
Author URL: https://archiveofourown.org/users/rehliamonster/pseuds/rehliamonster
Summary: What happened between Squish leaving and her finding Sans at the pool.A fanfic for the fanfic "The Party Incident and other embarrassing Anecdotes." This won't make sense unless you read that fic.





	The Public Restroom Incident

**Author's Note:**

  * For [poubelle_squelette](https://archiveofourown.org/users/poubelle_squelette/gifts).
  * Inspired by [The Party Incident and Other Embarrassing Anecdotes](https://archiveofourown.org/works/5798113) by [poubelle_squelette](https://archiveofourown.org/users/poubelle_squelette/pseuds/poubelle_squelette). 



> So my mind went places after I saw the comment on poubelle's latest chapter and because I'm a degenerate and she's awesome I got to write this and now here we are :,) 
> 
> I'd tell y'all to go follow my tumblr to support me but the place is burning down sinners like me so for now uh... I got nothing, folks. (I know written erotica is supposedly allowed to stay but the filters are crap and besides I don't trust them anymore. I'm currently trying pillowfort and shopping around for good sites to be on.)

You pushed by him and hurried towards the lockers.

Sans didn’t watch you as you left. He couldn’t. He’d done his part by offering you a towel and that was about all he could manage right now. Seeing you like this caught him off guard. It wasn’t something he was meant to see, especially not like this. After what happened with Papyrus and that lady, he knew that this was an important part of your body. Your most vulnerable. 

Your… 

No. Stop. He couldn’t think about it. He needed a distraction so he wouldn’t. His eye lights roamed around for something, anything. 

There it was. Your bikini top, floating innocently on the water. He stared at it. It was as if it was mocking him. Just a moment ago, you hadn’t been able to find it as you frantically searched for it, and now it was there. 

He bent over and fished it out, wrung it out a little. You’d probably gone to the locker room, so he’d have to go there to give the top back to you. If you didn’t get it back you wouldn’t be able to enjoy the rest of this day and he doesn’t want that. It’s way too often that your bad luck interrupts your fun. So he’d go to the locker room and you could put it on again. 

The thought felt like running into a brick wall and the wall was the image of you without your top. 

It returned to him with such force that for a moment it was as if he was choking. Instantly, he felt his bones heat up as his soul began to hum. Sweat began to gather on his forehead and the back of his neck as his magic went into overdrive. The tell-tale glow of his soul was already visible through his tank top. 

No. No, this was the worst. It was too bright, everyone would know what it meant if they saw him. _You_ would know. He couldn’t go to you like this. He couldn’t go to you anyway because you’d be in the changing room and he wasn’t allowed there but he also couldn’t give your top to someone else like this. To be so turned on just from seeing you, from seeing you in a situation that had been bad and embarrassing for you was pretty bad. He felt so ashamed of his reaction.

Quick, before anyone saw him. 

He shuffled away from the pool into the men’s restroom, walking perhaps faster than he normally would. There was a stall free at the very end; good. He walked in, ignoring the weird looks that followed him from the human men in here. Once he had locked himself in, he leaned against the door and tried to steady his breath. 

_fuck._

There was one pang after another in his soul, the hot feeling coming from it rolling through his bones. 

His magic was buzzing and buzzing and _buzzing_. 

Loud. 

Way too loud. 

He felt so sweaty and uncomfortable. That was a familiar feeling. One of his hands was already under his tank and on his ribs, his eye lights unfocused on the tiled wall ahead of him. The other hand clutched your top still. He looked at it as if it was a surprise to find it there and began to lift it before a last remnant of reason stopped him.

Was he really going to do this? 

One of his fingers caught on his ribs and he had to bite down a strangled noise. 

“Did you hear that?”

“Wow, that’s so weird.”

“I thought monsters don’t shit, man.”

“Who knows.”

Oh no. 

…

No, no, no. 

He couldn’t be doing this here. He shouldn’t. It was a dirty human bathroom stall. This wasn’t right. Even if it hadn’t been a dirty bathroom stall it wouldn’t have been right, he’d been about to sniff your top like some weird creep, so he had to stop and leave. 

Instead, his fingers sped up, pressing hard against the smooth plane of his sternum. 

His other hand made it all the way up until your bikini top was pressed against his cheek, wet and slightly cool. He imagined you standing in front of him, pressing against him while the two of you were being naughty in public. A shiver ran through him when he thought of that. You, so close. How you’d lean closer and whisper into his ear to be quiet. How you’d praise him for doing what you said. 

How you’d praise him in general.

Tell him how good he was doing. 

Sans stumbled forwards and away from the door, vaguely grateful that the walls separating the stalls reached all the way to the floor. This would be so much worse if his feet were visible from the outside. Not that it wasn’t bad enough already. He couldn’t believe that he was doing this at all, masturbating in a dirty human toilet stall, but it was as if his body had switched to autopilot. Everything was simply happening on its own, while he watched. 

That’s what he told himself as he leaned over the toilet, resting one of his hands on the tiles of the wall behind it. 

Not his fault. 

Not his choice. 

If he said it often enough, perhaps he could believe it and have deniability. 

Deniability for his actions, for the reason he was in here, for why he was over the toilet. For what he was about to do. Rubbing his sternum hadn’t been doing enough. It caused too much friction, and it wasn’t… it wasn’t what he needed or wanted right now. 

The soft blue glow in his pelvic region barely had time to appear before it sprang into the shape of a small pale blue cock. He wrestled his shorts down and gripped it, more magic already added to his hand to make it more like flesh, and it was only then that he remembered the bikini top. He was still holding it, in the hand he now had wrapped around his cock. The cold, wet fabric on his sensitive dick was a shock that almost startled him out of his frenzied state. 

It was like it was mocking him as he stared at it. Just a wet piece of fabric. But it had been on you. 

Sans had never felt as disgusted with himself as he did when he began to move his hand, the fabric of the bikini top giving him just the right amount of slick give and friction. 

He had to stop himself from moaning out loud. He barely managed to turn his head to the side and bite into his own arm, the one he was leaning on to support himself against the wall. It muffled the noise together with his efforts to swallow it down. He couldn’t be too loud. Nobody could hear. 

The wet _schlick – schlick – schlick_ sounds from where he was stroking himself with your top already sounded so obscenely loud to him. It wasn’t the only noise around - there were people walking and talking outside, the noises of the men doing their business, and whenever the door opened when someone walked in or out, the sounds of the water park filtered in, water splashing, children screaming in delight, people laughing. It should be enough to cover any noise he might make, as long as he wasn’t too loud. 

As long as he wasn’t too loud, he could keep going. 

Could think of you. 

Of how you looked, how _soft_ you’d been, your expression still so happy and excited from the slide. Soft and happy and good, and your soul so bright and beautiful, it was too much, it was way too much.

_He wanted to touch you so bad._

With a heaving sob, he bit harder into his arm and his whole body shuddered. The bones of his fingers clinked against the tiles where he rested and his bones rattled a little. Cum began to spill out of his cock in spurts.

It took him at least a minute to steady himself, where he could do nothing but focus on not letting his legs give out underneath him. Only then did his reason slowly return and with it an understanding of what he was looking at. 

“ _fuck,_ ,” he whispered to himself. 

Most of his cum had gone straight into the toilet as intended, but some of it had gotten caught on your bikini top. It was already setting in. 

Cold, hard panic immediately crashed into his soul and displaced the hot pleasure he had been feeling only moments before. 

No, no, no, no!

What had he _done_?

He was the worst. The absolute worst. It was bad enough that he had given in to the thoughts of you again, but to use an article of your clothing to masturbate with? Gross. He was such a piece of shit. 

Quick, quick he had to go and wash it out before the stain could set. He couldn’t believe he had done this and he had to get rid of all the evidence. Flushing the toilet came first. Barely taking a second to confirm that his shame was whirling down the drain, he listened at the door for a second. It seemed he was in luck at least; he couldn’t hear anyone out there right now. 

Opening the door of his stall, he practically ran over to one of the sinks and turned on the water. When he held your bikini top under it, the water ran down blue. 

Sans could feel his skull burn as he stared at the watery colour. This was so wrong. Worse than anything else he’d ever done since he met you. He grabbed your top with both hands and rubbed the fabric together, vigorously scrubbing to make sure it would all go away. There couldn’t be anything left. Hell, maybe he should just toss it in the bin and claim it was lost. Your fun day at the park would be over, but that would be better than giving this to you now in its filthy state. 

Yeah. 

He sagged with relief. 

That’s what he would do. 

Even though the stains were washing out well and he couldn’t see much blue on it anymore now, that was the right choice to make. He couldn’t seriously hand you this bikini top knowing what he’d done to it and watch you wear it. As disgusting as he was being, he wasn’t that far gone yet. 

The door to the restroom opened, but Sans didn’t really care. Or at least he thought he didn’t. 

“Oh, is that the top?! Awesome dude, you found it! Hand it over, I’ll give it back to her.”

Sans’ skull snapped up and his eye lights shrunk to the size of needles. 

“u-undyne?”

“In the flesh!!”

“this is the men’s restroom,” he pointed out helplessly, feeling incredibly stupid as soon as the words left his mouth. 

“Pfft, so? Do I look like I care?!”

Of course she wouldn’t. 

“Why are you holding that thing under water?” Undyne asked him curiously, her eye dropping down to what his hands were doing. 

“it fell on the floor and got dirty,” he said before he could even think about it. While he was grateful about his quick reply, he inwardly felt something curl up and die inside him. If this was how you felt every time something embarrassing happened to you he suddenly felt a hundred times more sympathy for you than before. This was the worst. He wanted to crawl into a hole and never come out again. 

“Well, it looks clean now,” Undyne decided and held out her hand. 

Sans stared at it. 

She’d question him if he didn’t give the top to her. 

And being Undyne, she’d have all these weird anime in the back of her mind, and might just reach exactly the right conclusion. 

He wrung out the top and gave it to her. 

“Awesome, thanks. Would’ve sucked if she’d have to just sit around now!” 

“yeah.”

“Hey are you okay? You’re quiet.”

“trying not to breathe. it doesn’t exactly smell like roses in here.”

“Well!! Good thing I don’t have a nose,” Undyne cackled. Then she left the room, presumably to find you and hand you the bikini top. 

Which you might then put on again. 

Sans slowly made his way out of the restroom and sat down at the edge of a pool. He didn’t really see the pool even though he was looking straight at it. 

He was too busy berating himself and regretting every decision that had led him here.


End file.
